Exhaust gas recirculation (EGR) systems are used for controlling emissions of undesirable pollutant gases and particulates during operation of an internal combustion engine. Such systems have proven particularly useful in internal combustion engines used in motor vehicles such as passenger cars, trucks, and other on-road machines. EGR systems generally recirculate exhaust gas into an intake air supply of the internal combustion engine. The exhaust gas reintroduced to the engine cylinder reduces the concentration of oxygen in the cylinder, which lowers the maximum combustion temperature, slows the chemical reaction of the combustion process, and decreases the formation of oxides of nitrogen (NOx). Furthermore, the exhaust gas typically contains unburned hydrocarbons which are burned after reintroduction into the engine cylinder further reducing the emission of undesirable pollutants from the internal combustion engine.
Sulfur, that may be present in fuel, may combine with oxygen at certain points in the EGR system to form sulfur trioxide. Relatively hot recirculated exhaust gas is cooled before being reintroduced into the cylinder by directing the exhaust gas through an air-to-gas or a water-to-gas heat exchanger. When the exhaust gas is cooled, water vapor in the exhaust gas may condense and combine with the sulfur trioxide to form sulfuric acid. Sulfuric acid can corrode the surface of the equipment and can lead to maintenance issues.
One system for detecting a corrosive compound in a system is described in U.S. Pat. No. 6,536,264 (the '264 patent), issued to Flammersfeld et al. Specifically, the '264 patent describes a liquid fluid system having a transparent component blocked by a corrodible barrier. Fluid flows through the system in such a way that the corrodible barrier is in contact with the fluid. If the fluid in the system becomes corrosive, the barrier may corrode and allow the fluid to flow into the transparent component. Fluid in the transparent component may then serve as a visual indication that the fluid in the system is corrosive.
While the system of the '264 patent may serve as a visual indication of corrosion in a liquid system, it may not be effective in a gaseous system. A corrosive compound in a liquid system may be in constant contact with the corrodible barrier and may be readily visible in the transparent component. Sulfuric acid in exhaust gas may not contact the corrodible barrier sufficiently to corrode the barrier quickly, and once the barrier corrodes the exhaust gas may not be readily visible in the transparent component.
The present disclosure is directed at overcoming one or more of the shortcomings set forth above or other shortcomings.